Probably somewhat silly newbie question

[James Stroud]

elgrandchignon at gmail.com wrote:
> Hi all--
> 
> Trying to learn Python w/little more than hobbyist (bordering on pro/
> am, I guess) Perl as a background.
> 
> My problem is, I have a list of departments, in this instance, things
> like "Cheese", "Bakery", et al. (I work @ a co-op health food store).
> I've populated a list, 'depts', w/these, so that their indexes match
> our internal indexing (which skips a few #'s).
> 
> Now, I'd like to simply generate-- and be able to refer to-- a bunch
> of other lists-sets (for subdepartments) by iterating through this
> list, and naming each of these subdepartment lists "categoryx", where
> x is the index # from the master 'depts' list.  And then be able to
> populate & refer to these lists by accessing their variable-including
> name.
> 
> In Perl, it's a fairly trivial matter to use a string variable in
> naming some other kind of variable-- not sure about Python though.  My
> initial, very weak stab at it (don't laugh!) went something like this:
> 
> for i in range(len(depts)):
>     if depts[i]:
>         categorylistdeptname = 'category' + str(i)
>         categorylistdeptname = []
> 
> Not sure what that wound up doing, but it sure didn't seem to work.

First, your are rebinding categorylistdeptname in the loop every time.

But you probably want a dict (in python 2.4 or later):


    deptdict = dict((dept, []) for dept in depts))

And this gets what you want, believe it or not.

Now you can populate each list:

    deptdict['Bakery'].append("Donuts")
    deptdict['Bulk'].extend(["Granola", "Rasins"])

And work witht the lists by name:

    for item in deptdict['Bulk']:
      print item
      # prints "Granola", "Rasins", etc.


James